1. Field of the Invention
The present invention is directed to a padding press. More particularly, the present invention directed to an improved padding press which is adapted to receive several sizes of stacks of paper to be padded, for applying a clamping force on the stack of paper by exertion of a minimal effort by an operator and for drying a glue or like adhesive substance which is utilized for binding together the stack of paper.
2. Brief Description of the Prior Art
Padding presses have been known in the art for a long time. During a padding operation, a stack of paper, usually consisting of identically-sized rectangular sheets, is placed upon a substantially flat surface so that the edges of the paper in the stack are aligned with one another. Usually, cardboards or like relatively stiff paper members are interspaced with the sheets of paper in the stack in order to provide a relatively rigid base for the individual pads. A clamping force is then brought to bear down on the stack and a glue or adhesive is applied to an exposed edge of the stack. After the glue or adhesive has hardened, the clamping force is released and the stack is separated into individual pads.
The padding presses or padding machines of the prior art are generally designed to enable an operator to perform the above-noted steps. For this purpose, the padding presses of the prior art generally include a support surface or board upon which the stack of paper is placed. An adjusting surface or board is usually provided in a substantially perpendicular position relative to the support board, and a manually operable and lockable clamping press is usually attached to the support board. The purpose of the adjusting board is to permit alignment of the edges of the sheets of paper in the stack adjacent to the adjusting board. After the clamping force is applied to the stack of paper, the adjusting board is usually removed so as to expose the aligned edges of the stack for the gluing step. In many of the prior art padding presses, the assembled support and adjusting boards are tiltable into a position wherein the stack of paper is pulled toward the adjusting board by the force of gravity. For the gluing step, the support board is, however, usually tilted back into a substantially horizontal position.
For a more detailed description regarding the state of the padding press manufacturing art, reference is made to U.S. Pat. Nos.: 4,146,942; 3,986,447; 3,889,590; 2,708,400; 2,641,781; 2,526,987; 2,494,424; and 1,354,061.
In some padding presses of the prior art, such as the ones described in U.S. Pat. Nos. 3,986,447 and 2,641,781 a separate clamping rack is provided to be used in association with a support rack. In these devices, the clamping rack holding the clamped-together stack of paper is removed from the support rack in order to expose a desired edge of the stack for a gluing operation.
Even though a relatively large variety of padding presses have been provided in the prior art, the prior art devices still need substantial improvement in several aspects. More specifically, a disadvantage of many of the prior art devices is that an operator is required to exert a relatively large physical force to provide sufficient clamping pressure to the stack of paper to be padded.
Another disadvantage of most of the prior art devices is that the devices are not adapted for receiving continuously varying sizes of papers for alignment for the padding operation. In other words, most prior art devices are adapted to receive either only one size of paper or only several predetermined sizes of paper.
Still another disadvantage of the prior art devices is that the glue or adhesive applied to the edges of the papers is dried by a mere passive air drying process. Stated differently, in the prior art, an operator must wait until the glue or adhesive dries and binds; the drying and binding process is not aided by application of heat or forced circulation of air. It will be readily appreciated by those skilled in the art, that the delay occasioned by waiting for an appreciable amount of time for the glue or adhesive to dry while the stack of paper is clamped in the padding press, is inconvenient. It also increases the cost of the final padded paper products.
The present invention is directed to an improved padding press which overcomes or minimizes the above-noted disadvantages of the prior art.